Science is a communal activity that is best advanced with collaborations both intellectual and experimental. All investigators in this grant have office and laboratories in contiguous space on the fifth floor of the Center for Cancer Research. The overlapping research interests and collaborations of laboratories in the program will be strongly reinforced by the sharing of essential facilities. The Genomics Core is the central facility of this shared core. This will generate resources for transcriptional and genomic arrays and high throughput genotyping of mammalian systems. It will also provide critical technical advice on the preparation and screening of samples and analysis of the resulting data. In addition, as students and fellows begin to apply these techniques to new questions, it will act as an essential area of expertise that will help to communicate technical limitations or advances to all four groups in the program. To promote further interactions and to more cost-effectively use large equipment, the four groups will share several other common facilities. These include -200 degree cell line storage devices (some liquid nitrogen-cooled), -70 degree freezers, ultracentrifuges and rotors, intermediate speed centrifuges (Sorvall), gel dryers and vacumn pumps, bacterial fermentation facilities, spectrophotometer, phosphorimager, dark room with automatic developer, and scintillation counter. This equipment is located in three communal rooms that are accessible from public halls. The four groups share the work of a lab aide who is responsible for handling glassware. The four groups also share a common dry ice chest that is located with direct access from the hall. The sharing of these common facilities and equipment is important for building a feeling of shared responsibility, goals, and ideas among the four laboratories. It also increases the intensity of use that reduces costs. Finally, as students and fellows compete for use of this equipment, they exchange ideas and begin collaborations. The sharing of common equipment breaks down the isolation of the four groups.